The process of manufacturing semiconductor substrates (hereinafter, simply referred to as “substrates”) conventionally involves various types of processing performed by a substrate processing apparatus on substrates having an insulation film such as an oxide film. One example is cleaning processing for removing particles or the like adhering to the surface of a substrate by supplying a cleaning liquid to the surface of the substrate.
In a substrate cleaning device disclosed in Japanese Patent Application Laid-Open No. 2010-56376 (Document 1), a piezoelectric element vibrates a cleaning liquid retained in a cylindrical body of a cleaning nozzle so as to cause a plurality of outlets to eject droplets of the cleaning fluid toward a substrate. In a substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2012-182320 (Document 2), a nozzle for ejecting droplets of a processing liquid toward a substrate is provided with a plurality of rows of outlets. In a substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2012-209513 (Document 3), a nozzle having a plurality of rows of outlets are moved along a track that passes through the center of rotation of the substrate.
Japanese Patent Application Laid-Open No. 2012-9812 (Document 4) discloses a liquid processing device in which a processing liquid is supplied onto a substrate from 11 nozzles that are arranged in a straight line. With this device, areas ranging from the tips of these nozzles to the surface of the substrate are irradiated with lines of laser light, and images of liquid columns of a resist liquid ejected from the respective nozzles are captured with a camera directed to the areas. The result of the image capture is then compared with reference information, which is obtained in advance by capturing images of the resist liquid ejected normally from the nozzles, so as to determine whether or not the resist liquid is ejected from each of the nozzles and whether or not there is a change in the ejection state.
Incidentally, if substrate processing apparatuses as disclosed in Documents 1 to 3 are used to observe a processing liquid ejected from nozzles toward a substrate as in Document 4, reflected light from the substrate may enter the camera. There is also a concern about the influence that droplets, mist, or the like of the processing liquid having collided with the substrate would have on the accuracy of inspection. It is also conceivable that disposing constituent elements such as a camera and a light source at appropriate positions may be difficult due to a variety of structures, such as a cup part for receiving a processing liquid dispersed from a substrate being disposed around the substrate.